What is Life?

A living organism is a collection of biomolecules that are well organized, maintain equilibrium, and carry out Energy Transfer and Transformation.

A living organism has the ability to grow, adapt and reproduce.

The existence of species is a result of evolution. Random mutations which get accepted become adaptations and are carried to the next generation via genes.

Several processes intracellular, cellular, extracellular, etc operate to maintain this equilibrium. The complexity of the survival mechanism increases as we move from simple to complex organisms.

The human brain can be considered as a chief center of maintenance of survival mechanisms.
If we inject some pathogenic bacteria into the body; our immune system will produce antibodies and inflammation response to survive; to maintain the equilibrium; to protect our body.

Consider a person who is in front of a tiger cage and needs to solve a puzzle in a given time to escape or else he would be fed to the tiger. A person’s brain will carry out processes to ensure survival.
The human brain is what kept him surviving and thriving from the tropics to the deserts to the mountains and the plains. 

The question is WHY?
And
WHY There is life?

And WHY there are these processes to sustain life and reproduction?

The answer to WHY goes very deep and CAN be explained and learned from a study that we call Physics.

Life is a spontaneous process.

There are four basic forces that we know of 

1. Gravitational Force
2. Electrostatic Force
3. Nuclear Force
4. Weak Forces

These forces are the reason, for which there is life. Every aspect of life, from cognition to our actions, family, and love are the spontaneous outcomes of these forces that operate on the matter that they are made of.

Human knowledge is limited.
We only know this universe by only 5 senses –

1. Vision
2. Hearing
3. Taste
4. Touch
5. Smell
 

We only know the things which are related to these senses. We cannot think of anything which does not involve any of these senses.

Try it! Try thinking a thought that doesn't involve any of these senses 
So our knowledge and ability to understand everything is very limited.

But still, I will try to answer all these WHYs 

WHY there is life?

The best answer to this question could only be that because there can be life. The universe and planet that we live on have what it needs for life to originate. 

It is reasonable to hypothesize that elements needed for life, could be arranged by the physical and chemical occurrences to give birth to the first living cell. 

The processes that made carbon, hydrogen, oxygen, nitrogen, sulfur, phosphorus combine and evolve into conjugated molecules, compounds, amino acids, carbohydrates, proteins, etc. 

The most important step that occurred was when these molecules got trapped by a bilayer of phospholipid that we call cell membrane or plasma membrane. It became a protective coat to these early biomolecules. A plasma membrane would only allow selected molecules to enter or exit.

A crucial requirement for any organism to survive is to maintain its integrity.
If integrity is lost an organism is dead. DNA and RNA maintain this integrity. A cell manufacture various proteins, carbohydrates and lipids for its integrity and it uses energy; energy to make new chemical bonds.

The earliest organisms trap the energy of the sun and used it to synthesize compounds and new bonds. So metabolism which is essentially an energy transfer and transformation is a main defining characteristic of a living organism and it also makes a living organism in a dynamic state with its environment.

Since life started; organisms grew in number and size and evolution took its course. 

There are two types of answers, that a human seeks to comprehend the reality, available to him. 

The first type of answer is science and is scientific, but it does not satisfy, it never can, so the urge for the other answer, has less to do with really knowing, but has more to do with a myth that can be formed to give subjective meaning to the reality. For this other reason, I feel comfortable to say -

NOTHING HAPPENS FOR A REASON. Things just happen, reasons are made by humans. Everything that occurs is due to physical reactions which are spontaneous in a given state of time, pressure and volume.

Environment and errors in replication bring about random changes to the DNA or the genetic material of a living organism. Some of these changes are harmless, some are harmful and some are useful and increase the chances of survival. If the organism survives a change, it is transmitted to its progeny. The process continuous and the result is evolution – the origin of new species. These changes or mutations are random. However, the process of evolution is not random. Natural selection is the opposite of randomness.

We humans as a species are a result of this natural selection. I should mention that this natural selection is not a 'creation process, it is an editing process. It is not a cause, it's the effect. 

You can assume any kind of a divine purpose for human existence. But there's no evidence to suggest that our existence is anything more than the spontaneous reactions in nature. 

Human beings are special but there was no 'need' for them to exist. Our single-cell relatives can completely survive and maintain their integrity.

Human Brain -

It is the only thing in the known universe which is trying to understand itself. The network of neurons turned out to be excellent for the survival of multicellular organisms. The primitive brain of lower organisms had limited functionality; receiving information about the environment through senses and making a response.
But the human mind is well developed and has emotions, feelings of desires, pleasures, and intelligence.

Reward mechanism in our brains has produced desires, pleasure. They prevent demise and keep us eating and reproducing. The sensation of pain and reflex actions make a human and animals stay away from danger. Higher functions of our brain combined with basic functions and desires are responsible for maintaining the structural and functional integrity of a collection of biomolecules.

After being born a child becomes so much addicted to the pleasures that he would not want to die but to live and explore more pleasures.
It is very interesting to note that this brain, which is the product of natural selection, can work opposite to the natural selection.

Evolution is a blind watchmaker, it has no mottos, no aims, no objectives.

It has no liability to the species. 99 percent of the species that ever existed became extinct. It's a slow process, that animated the life on earth. 

The brain however can foresee the future, it can make plans, the actions, it does, are thought out, are made by planning for the future.

Higher intellect helped us to develop antibiotics, vaccines, technology. We developed moral sensibility, religions, ideologies, science, social science and politics. We learned to grow our food and enhanced productivity as our population grew. 

How good is this brain? The same brain that took humans to the moon also is responsible for terrorism, hatred, social divide based on religion, casts, countries. We no longer fight for the food, we fight and kill each other, for the superiority of our culture, our country, our flag, our caste, etc. We have developed bombs that can wipe out entire species, in minutes. 

"There is no evidence that help will come from outside that will save us from ourselves" - Carl Sagan.
 

The existence of our species, depend upon the cumulative effect of our brain, it can lead us to cure AIDS, or it can lead us to our doom. Till now, the brain is the reason we survive, despite all evils it has caused. 

We all share the responsibility to flourish and protect our species, our environment, so we can all enjoy nature's bounty. So we can love and get loved. 

In writing of this blog, I don't claim to know the Ultimate Truths, That's the realm of religions; to know the 'Ultimate Truths'. I see no adventure in pretending to know truths or ultimate truths. Nor do I find any reason to believe that there could be something like The Ultimate Truth.

"For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring". -  Carl Sagan